CN1622281A - Method for producing semiconductor device and cleaning device for resist stripping - Google Patents

Abstract

A semiconductor device manufacturing method and a cleaning apparatus for stripping a resist provide a semiconductor device having excellent element characteristics with a sufficient yield in the following manner, after dry etching of a photolithography process, the resist is removed by wet cleaning agent, and sufficiently removes particles or metal impurities without damaging fine patterns. A method for manufacturing a semiconductor device includes forming a resist pattern on a film provided for a semiconductor substrate, forming a fine pattern of a conductive film using the resist pattern as a mask while performing dry etching, supplying a resist stripping solution to The fine pattern formation surface of the semiconductor substrate is processed by a single wafer system to remove the resist pattern, and to perform the rinsing process of the semiconductor substrate.

Description

Manufacturing method of semiconductor device and cleaning device for removing resist

This application is based on Japanese Patent Applications No. 2003-394249 and No. 2004-324601, the contents of which are incorporated herein by reference.

technical field

The present invention relates to a manufacturing method of a semiconductor device and a cleaning device for removing a resist using the same method.

Background technique

Usually in the manufacture of a semiconductor device, fine pattern formation of a gate electrode or the like is performed in such a manner that a resist film is formed on a conductive film provided on a semiconductor substrate, and then the resist obtained by patterning the resist The resist pattern of the etchant film is used as a mask for dry etching, and the conductive film is patterned into a predetermined size and shape. As a technique for stripping the resist after patterning, so-called SPM cleaning using a mixed solution of sulfuric acid and hydrogen peroxide, followed by rinsing treatment with pure water is performed.

This SPM cleaning is also performed in the following manner: SPM is filled inside a treatment tank made of acid/heat-resistant material such as quartz, and then the SPM is kept at a predetermined temperature, after which the wafer is soaked in the SPM, which is called Immersion type treatment. After SPM cleaning, the wafer is soaked in a treatment tank filled with pure water, followed by soaking type rinsing treatment, and finally drying treatment of the wafer.

As for the immersion type cleaning method, for example, Japanese Laid-Open Patent Laid-Open No. Hei 9-017763 discloses a batch process according to a cassette system in which a cassette accommodating a plurality of wafers is inserted into a processing tank while performing cleaning, and does not use simultaneous processing. Batch processing of cassettes of multiple wafers in accordance with the cassette system.

On the other hand, Japanese Laid-Open Patent Laid-Open No. Hei 5-121388 discloses a cleaning method of a so-called single-wafer type processing system in which wafers are processed one by one to solve Difficulty in controlling cleaning conditions due to increase in size, etc.

The immersion system performs processing while immersing multiple wafers in the processing tank. This system has the advantage of being able to process multiple wafers at a time, but multiple wafers are soaked side by side in the processing solution, and for this reason, the contaminants removed from the backside of the wafers are dissolved or dispersed in the aqueous solution, after which, in some cases , the contaminants will reattach to the adjacent surface of another wafer. On the other hand, a single-wafer type system is a system that processes wafers one by one, in which the wafers are horizontally fixed on a fixed table, and a process of spraying a process liquid onto the wafer surface while rotating in the wafer plane is performed. According to this system, there is no problem of contamination caused by another wafer, and thus processing can be performed with a high degree of cleanliness.

In the manufacturing process of semiconductor devices, wet processing using a processing liquid, such as cleaning, etching, separating a resist layer, etc., is frequently performed. As an apparatus for performing such a wet treatment, there are a rough-type immersion system apparatus and a single-wafer type apparatus. A soaking system is a system that simultaneously soaks a plurality of wafers in a processing tank while performing processing. The system described above has the advantage of being able to process a plurality of wafers at a time, however, the plurality of wafers are immersed side by side in the processing solution, and for this reason, the contaminants removed from the backside of the wafers are dissolved or dispersed in the aqueous solution, after which, In some cases, the contaminants reattach to the adjacent surface of another wafer. On the other hand, a single-wafer type system is a system that processes wafers one by one, in which the wafers are horizontally fixed on a fixed table, and a process of spraying a process liquid onto the wafer surface while rotating in the wafer plane is performed. According to this system, there is no problem of contamination caused by another wafer, and thus processing can be performed with a high degree of cleanliness.

Japanese Laid-Open Patent Laid-Open No. Hei 6-291098 describes a single wafer type substrate cleaning apparatus. This device effectively uses _the heat of mixing generated by mixing the _H2SO4 solution with _{the H2O2} used to speed up the reaction. That is, the H ₂ SO ₄ solution and the H ₂ O ₂ solution are sprayed from different nozzles. The two solutions are mixed at _the mixing point in the shortest range just below the nozzle, and a _H2SO4 - _{H2O2 mixed} solution (called sulfuric acid/hydrogen peroxide) is prepared. The mixed solution drops near the center of the rotating photomask substrate and spreads by centrifugal force. By controlling the flow rates of H ₂ SO ₄ and H ₂ O ₂ , the height of the mixing point P, the number of revolutions of the substrate, and the temperature distribution of the mixed solution on the surface of the substrate are limited to a minimum, and uniform cleaning can be achieved. Wet stripping that can use chloromethylstyrene-based resist materials for electron beam lithography and the like has been introduced.

However, this device uses a system in which two liquids are sprayed from nozzles and then mixed to utilize heat from the mixing point of the two liquids, so it is difficult to control the liquid temperature when the liquid reaches the wafer surface. In particular, in Figures 2 and 3 of the same document and the prior art description of Examples 1 and 2 (paragraph 0035), it is introduced that the large fluctuation of the wafer surface temperature distribution depends on the nozzle height, and that there is an optimum nozzle height. value. Therefore, it is difficult to control the wafer surface temperature, and therefore it is difficult to stably obtain a preferable processing efficiency.

Contents of the invention

In recent years, due to the pattern micro-manufacturing brought about by the high integration of semiconductor devices, higher cleanliness is required, and conventional immersion-type cleaning methods cannot handle this situation, thus the problem of particles or metal impurities adhering to the wafer surface become conspicuous.

In a manufacturing process such as a photolithography process, a large number of particles or metal impurities adhere to a wafer. In this case, when the immersion type SPM treatment of a plurality of wafers is performed while arranging side by side, the particles adhering to the backside of the wafers are separated in the liquid, and thereafter the adhesion of particles to the opposite face (wafer surface) of the wafers arranging side by side occurs The phenomenon. In order to remove the adhered particles, the process is done adding megasonic waves in the soak type rinse process, however the side effect is to damage the fine patterns on the wafer, whereby in some cases, the problem of missing patterns occurs. In the case of a specific pattern width of not more than 150 nm, this problem becomes serious. Also, metal impurities adhering to the wafer dissolve in the solution and then build up as the SPM is used again, causing a problem of metal contamination on the wafer surface.

The purpose of a non-limiting example of the present invention is to manufacture a semiconductor device with excellent element characteristics and a sufficient yield in the following manner: after dry etching of the photolithography process, or after ion implantation or wet etching through the openings of the photolithography process After opening the resist pattern, the resist is stripped by wet cleaning, and particles or metal impurities are sufficiently removed without damaging fine patterns.

According to the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming a resist pattern on an upper portion of a semiconductor substrate, performing processing using the resist pattern as a mask, and holding the semiconductor substrate horizontally while rotating the semiconductor substrate. In the case of a semiconductor substrate, the resist stripping solution is supplied to the resist pattern forming surface of the semiconductor substrate while stripping the resist pattern, wherein the step of stripping the resist pattern includes: supplying the resist stripping solution to A resist pattern forming surface while rotating the semiconductor substrate at a higher speed as a first step; and a first step of supplying a resist stripping liquid to the resist pattern forming surface while rotating the semiconductor substrate at a lower speed After the second step.

According to the present invention, a first step of supplying the resist stripping solution while rotating the semiconductor substrate at a higher speed and a second step of supplying the resist stripping solution while rotating the semiconductor substrate at a lower speed are included. For this reason, the resist pattern can be effectively stripped. In particular, it is possible to effectively peel off portions that are difficult to peel off by a normal peeling process, such as a resist hardened layer in a resist pattern, and the like.

In the present invention, in the process of performing the treatment, it is possible to use a resist pattern as a mask to perform ion implantation on the entire surface.

Also in the present invention, the doping amount in ion implantation is not less than 10 ¹⁴ cm ^-2 , and the resist hardened layer generated in the resist pattern caused by ion implantation can be stripped by the second step.

Also in the present invention, a constitution may be adopted in which a resist pattern is formed on a film provided on a semiconductor substrate, and in the step of performing processing, selective dry etching of the film is performed using the resist pattern as a mask.

Here, the fine pattern described above may have a portion with a width not greater than 150 nm.

Also, the fine pattern described above may have a portion having a width of not more than 150 nm and a height-to-width ratio of not less than 1.

The fine pattern described above may be a gate pattern, such as a SiGe gate pattern having a SiGe layer containing Si and Ge, a polysilicon or amorphous silicon gate pattern, or a metal gate pattern.

The following liquids can be used as resist strippers:

(i) Liquids containing peroxomonosulfate

(ii) Organic solvents

(iii) a mixture of a first liquid containing an acid and a second liquid containing hydrogen peroxide (for example, sulfuric acid and oxygenated water)

A constitution may be employed in which, for example, a first liquid containing an acid and a second liquid containing hydrogen peroxide are mixed in an airtight space, the resulting mixture is used as a resist stripping liquid, and the resist stripping liquid is supplied to the resist via a nozzle. Figures form the surface. Also, the first liquid and the second liquid are preheated to a predetermined temperature. Also, a configuration may be adopted in which sulfuric acid is supplied to the resist pattern forming surface before the first step using a resist stripping solution.

In the present invention, the resist stripping liquid is supplied to the resist pattern forming surface by means of a plurality of nozzles. Also, the resist stripping liquid is supplied to the resist pattern forming surface after the resist stripping liquid is previously heated to a predetermined temperature.

Furthermore, in the present invention, the adopted configuration further includes: performing a rinsing treatment on the semiconductor substrate after the step of stripping the resist pattern, and in the step of performing the rinsing treatment, while performing the rinsing treatment, the rinsing solution is supplied to the On the semiconductor substrate held by the holding unit, the semiconductor substrate held by the holding unit is dried while the semiconductor substrate is rotated by the rotating unit.

Here, the rinsing liquid may be lye, electrolytic cathode water, or hydrogen-dissolved water. The electrolytic cathode water is a liquid produced on the cathode side when electrolysis of pure water or water containing a small amount (not more than 0.5% by mass) of ammonium ions is performed. As a generating device for obtaining electrolyzed cathode water, although a two-tank type electrolysis system can be used, a three-tank type device can also be used. For electrolysis of cathode water, hydrogen gas generated at the cathode by electrolysis or hydrogen gas from a cylinder dissolved into water in weak ammonia water is required.

Also in the present invention, an employable constitution further includes: cleaning the semiconductor substrate from which the resist pattern has been peeled off with hydrofluoric acid, and cleaning the semiconductor substrate cleaned with hydrofluoric acid with a mixture of ammonia water and oxygen-containing water.

Also in the present invention, there is provided a resist stripping cleaning apparatus having a processing chamber for a single wafer system, comprising: a holding unit holding a semiconductor substrate, a rotating unit rotating the semiconductor substrate held by the holding unit, A resist stripping liquid is supplied to a cleaning liquid supply unit on a semiconductor substrate held by the holding unit, and a rinse liquid supply unit is supplied to a rinse liquid on the semiconductor substrate held by the holding unit.

Also in the present invention, there is provided a resist stripping cleaning apparatus having a first processing chamber for a single wafer system and a second processing chamber for a single wafer system, wherein the first processing chamber for a single wafer system Including: a holding unit for holding a semiconductor substrate, a rotating unit for rotating the semiconductor substrate held by the holding unit, a cleaning liquid supply unit for supplying an acid resist stripping liquid onto the semiconductor substrate held by the holding unit, and rinsing A rinsing liquid supply unit that is supplied to the semiconductor substrate held by the holding unit, the second processing chamber for the single wafer system includes: a holding unit that holds the semiconductor substrate, a rotation unit that rotates the semiconductor substrate held by the holding unit , a cleaning solution supply unit that supplies an alkali resist stripping solution onto the semiconductor substrate held by the holding unit, and a rinse solution supply unit that supplies a rinse solution onto the semiconductor substrate held by the holding unit.

In this apparatus, a configuration that can be adopted further includes heating means for heating the resist stripping means, and heat insulating means for thermally insulating the heated resist stripping liquid.

According to the present invention, a semiconductor device excellent in element characteristics and with a sufficient yield can be manufactured in such a manner that after dry etching of the photolithography process, wet cleaning strips the resist, and the adhesion of particles or metal impurities is sufficiently suppressed while No damage to fine graphics.

Description of drawings

From the following description in conjunction with the accompanying drawings, the above and other objects, advantages and features of the present invention will become more apparent, wherein:

Fig. 1 is a schematic structural diagram of the processing chamber of the resist stripping cleaning device of the present invention;

Figure 2 shows the results of the evaluation of the number of particles on the wafer surface after the resist stripping process;

3 shows the results of evaluation of the amount of metal (Ge) adhered to the wafer surface after the resist stripping process;

Fig. 4 shows the evaluation result of pattern peeling on the wafer surface after the resist stripping process;

Figure 5 shows a process sectional view of a process performed in one embodiment;

Fig. 6 shows the transition of the number of revolutions of the wafer in a process carried out in the embodiment;

Fig. 7 shows cleaning effect diagram in the embodiment;

Figure 8 (1 to 5) shows a schematic diagram of the resist stripping process;

Fig. 9 shows cleaning effect diagram in the embodiment;

Fig. 10 shows cleaning effect diagram in the embodiment;

FIG. 11 shows a schematic structural diagram of a substrate processing apparatus 100 according to an embodiment;

Fig. 12 shows a structural example of a substrate mounting table;

Figure 13 shows a structural example of the mixing section;

FIG. 14 shows a schematic structural diagram of a substrate processing apparatus 100 according to an embodiment;

15A, 15B are diagrams illustrating the positional relationship between the nozzle and the semiconductor substrate;

Fig. 16 shows a schematic structural diagram of a substrate processing device in an embodiment;

Fig. 17 shows an enlarged view of a part including a mixing part, a pipe and a nozzle;

Figure 18 shows a transition diagram of wafer revolutions;

Figure 19 shows a transition diagram of wafer revolutions;

Figure 20 shows a transition diagram of wafer revolutions;

Figure 21 shows a transition diagram of wafer revolutions; and

Fig. 22 shows a configuration example of the mixing section.

Detailed ways

The invention is described herein with reference to exemplary embodiments. Those skilled in the art will recognize that many alternative embodiments can be accomplished using the teachings of the present invention and that the invention is not limited to the embodiments described for illustrative purposes.

Hereinafter, preferred embodiments of the present invention are described while illustrating a method of manufacturing a semiconductor device having a gate electrode comprising a SiGe layer.

First, a silicon oxide film is formed as a gate oxide film by thermal oxidation on a silicon substrate on which an element isolation region is formed. The thickness of the silicon oxide film can be appropriately set within a range of, for example, 1 to 10 nm.

Next, a SiGe film is formed on the silicon oxide film by, for example, LP-CVD (Low Pressure Chemical Vapor Deposition). The thickness of the SiGe film can be appropriately set within a range of, for example, 1 to 400 nm. While the composition of the SiGe film can be appropriately set, the composition of Ge is set to 10 to 40 atomic % from the viewpoint of device characteristics. When the SiGe layer is a two-component system of Si and Ge, the Si composition at this time can be set in the range of 90 to 60 atomic %.

Next, a film is formed on the SiGe film. The film thickness is appropriately adjusted within a range of, for example, 10 to 400 nm. A polysilicon film can be used; and the polysilicon film can be formed in a manner such as depositing a polysilicon film by CVD, doping n-type or p-type impurities while depositing, or doping n-type or p-type impurities by ion implantation after deposition Impurities.

Subsequently, a photoresist is applied on the film (or on the impurity-doped SiGe film in the case where no film is provided) to form a resist film, and a predetermined resist pattern is formed by photolithography.

Thereafter, a gate electrode and a gate insulating film composed of a SiGe layer and a conductive material layer are formed, while film dry etching is performed on the SiGe film and the silicon oxide film using the resist pattern as a mask. Dry etching conditions can be appropriately set, and specifically, dry etching can be performed by a reactive ion etching method using, for example, Cl ₂ , HBr, or the like as an etching gas.

In the manner described above, a resist stripping solution is provided on a semiconductor substrate on which a gate pattern is formed, and thereafter, the resist pattern is stripped together with etching residues by wet processing of a single wafer system.

For the method of peeling off the resist pattern, in some cases, dry processing such as ashing etc. other than dehumidification processing is performed because such processing utilizes high energy such as oxygen plasma etc., which easily damages the substrate , a treatment to remove ashing residue is required, and thus a wet treatment using a resist stripping solution is advantageous.

It is preferable that the resist stripping solution can sufficiently strip the resist pattern after the dry etching by the single wafer system process. For the resist stripping solution, various inorganic solvents and organic solvents are known, specifically, for example, SPM (a mixture of sulfuric acid and hydrogen peroxide) is used as an inorganic solvent, and for an organic solvent, a solvent containing phenol and a halogen base can be used as an organic solvent. Solvents for main components, amine-based solvents, and ketone-based solvents, such as cyclopentanone, methyl ethyl ketone, etc. Resist after dry etching along with its surface denaturation, whereby usually the solubility of the solvent is low compared to the resist before dry etching, so resist residues tend to remain, so it is preferable to perform stripping with high resist Effective SPM cleaning.

For removal performance and cleaning effect, the composition of SPM can be set as sulfuric acid: 30% by mass, oxygenated water = 1:1 to 8:1 (volume ratio); working temperature is in the range of 100 to 150°C.

The resist stripping solution is supplied in such a manner that the resist stripping solution contacts the resist pattern forming surface of the semiconductor substrate; specifically, the resist stripping solution may be continuously or intermittently supplied while stripping the resist or provided after Hold for the scheduled hold time. At this time, uniform contact can be made between the surface of the semiconductor substrate and the resist stripping liquid while the semiconductor substrate is fixed to the turntable to be rotated; due to this, more efficient cleaning can be performed. Moreover, at the start time of providing the resist stripping liquid, when the substrate is rotated at a relatively high speed, the resist stripping liquid immediately occupies the entire semiconductor substrate, and thereafter, the resist stripping liquid can also be maintained for a predetermined period of time. Simultaneously spin the substrate at a lower speed or stop spinning.

Furthermore, it is preferable that the resist stripping liquid is supplied to the surface of the semiconductor substrate after being heated to a predetermined temperature in advance by a heating means such as a heater. At this time, it is preferable that the resist stripping liquid inside the pipe is kept at a predetermined temperature while providing a heat insulator such as a heat insulating material or a heater for heat insulation. In the case of using SPM, it is preferable to set the temperature at 100 to 150°C. A sufficient cleaning effect can be obtained in a short time by using a heated resist stripping solution.

It is preferable to provide the heated resist stripping solution on the heated semiconductor substrate while heating the semiconductor substrate, however, since a sufficient cleaning effect can be obtained without heating the semiconductor substrate in terms of simplifying the device structure and handling operation , preferably the heated resist stripping solution is provided on the semiconductor substrate at room temperature. Also, a resist stripping solution at room temperature can be provided on a heated semiconductor substrate, especially when using SPM, but SPM has a large specific heat and high viscosity, and since single-wafer system processing, the substrate and cleaning solution The contact time between them is short, and therefore, it is difficult to increase the temperature of the cleaning solution supplied on the substrate to the required temperature, and the cleaning effect becomes worse compared with the case of using a heated resist stripping solution.

In the present invention, it is particularly preferable to use SPM as the resist stripping solution. SPM has high viscosity and high corrosion characteristics, so SPM is usually used in immersion type processing, therefore, single wafer system processing using SPM does not present problems on the device in the case where the device is required to provide a heat-resistant or acid-resistant structure, etc., For this reason, single-wafer system processing is not required. In particular, in the resist stripping after dry etching of the photolithography process, as described above, it is difficult to remove the resist compared with the case before dry etching. The processing time of the system is generally shorter than that of the single chip system processing. That is, due to resist stripping after dry etching of the photolithography process, there is generally no technical idea of performing single-wafer system processing while providing a heated SPM on a semiconductor substrate.

After the resist pattern is stripped in the manner described above, the rinsing treatment in the single-wafer system processing is performed while supplying the rinsing solution on the upper surface of the semiconductor substrate. By this rinsing treatment, the liquid on the surface of the semiconductor substrate and the residue in the stripping liquid can be removed. Pure water may suitably be used as a rinse. For other rinsing liquids, _CO2 water that dissolves _CO2 into pure water, and water that reduces hydrogen gas into pure water can be used. Trace amounts of ammonium hydroxide (in the order of 10 ppm) can also be added to the reduced water. During the rinsing process, the semiconductor substrate is held on the rotary table to rotate, whereby uniform contact between the surface of the semiconductor substrate and the rinsing solution can be achieved, and more efficient rinsing can be performed.

Dry etching may be performed after the rinse treatment in such a manner that the semiconductor substrate is fixed on a rotatable stage and the stage is rotated at a high speed (for example, 1000 rpm). At this point, dry processing can be performed while blowing isopropanol vapor or dry inert gas. Due to high-speed rotation and further blown gas can be effectively dry.

It is preferable to perform the resist stripping process and the rinse treatment process continuously in a single wafer system. Furthermore, it is also possible to perform the drying process in one processing chamber of the single wafer system. This avoids contamination during wafer handling.

In the case of using an acid resist stripping solution such as SPM after this treatment, it is preferable to perform the treatment in a different chamber when treating the semiconductor substrate with an alkaline chemical solution. It can prevent the acid and alkali components in the chemical liquid from forming salts and producing particles.

After the processes described above, a predetermined semiconductor device can be manufactured on the semiconductor substrate on which the gate pattern is formed by a known manufacturing process.

Here, the embodiment taking the formation of SiGe gate pattern as an example is introduced, and the present invention also preferably forms a metal gate pattern made of tungsten or molybdenum, or forms a metal gate pattern made of NiSix, ZrN, TiN, IrSix, PtSix, etc. metal grid pattern. Also the present invention preferably forms a fine pattern having a portion having a line width of not more than 150 nm, and forms a fine pattern having a line width of not more than 150 nm and a height of not less than 1 relative to the line width. In particular, the present invention preferably forms a fine gate pattern having a gate length not greater than 150 nm, and forms a fine gate pattern with a gate length not greater than 150 nm and a ratio of gate height to gate length not less than 1. When megasonic waves are added in the soak-rinse process to remove particles adhering to the substrate in the conventional soak-type resist strip process, the fine-pattern resist lift-off pattern is susceptible to damage such as pattern lift-off and the like. According to the present invention, there is no need to add such megasonic waves, so the resist can be stripped while suppressing adhesion of particles or metal impurities without damaging fine patterns.

In the manufacturing process described above, the semiconductor substrate from which the resist pattern has been rinsed is cleaned (DHF cleaning) with hydrofluoric acid (diluted hydrofluoric acid: DHF), and then, if necessary, a The semiconductor substrate cleaned with DHF is cleaned with a mixture of ammonia water and oxygen-containing water (APM) (APM cleaning) after the rinsing treatment, and then, if necessary, a rinsing process is preferably performed.

DHF is strong in stripping dry etching residues, and APM is strong in particle stripping, so by performing these cleanings, dry etching residues and particles can be removed more effectively.

The concentration of hydrofluoric acid in DHF is preferably not less than 0.05% by mass, more preferably not less than 0.1% by mass, particularly preferably not less than 0.13% by mass, on the other hand, the concentration is preferably not more than 1.0% by mass, more preferably not more than 0.7% by mass, Especially preferably not more than 0.5% by mass.

When the concentration of hydrofluoric acid of DHF is high, the stripping ability of the dry etching residue becomes large, however, when the concentration of hydrofluoric acid is too high, the etching rate of the gate oxide film becomes large, thereby the etching rate becomes large to The extent to which side erosion is problematic.

Also, when the concentration of hydrofluoric acid is too high, the cleaning time needs to be shortened to prevent undercutting, whereby dry etching residues tend to remain, and it is difficult to control the cleaning operation in terms of controlling the cleaning time. Conversely, when the concentration of hydrofluoric acid is low, the etching rate of the gate oxide film decreases, thereby suppressing side etching of the gate oxide film, but the ability to remove dry etching residues decreases. Therefore, when the composition of the first chemical liquid is set within the range introduced above, the dry etching residue adhering to the semiconductor substrate can be further sufficiently removed, and at the same time, the side etching of the gate oxide film can be further sufficiently suppressed.

The working temperature of DHF is preferably not higher than 40°C, more preferably not higher than 35°C, especially preferably not higher than 30°C. By setting the working temperature of the DHF within the range introduced above, the side erosion of the gate oxide film can be further effectively suppressed. Also, the working temperature of DHF is preferably not less than 5°C, more preferably not less than 10°C, particularly preferably not more than 15°C. By setting the working temperature of the DHF within the range introduced above, the dry etching residue adhering to the bottom can be further fully removed.

As an example of the DHF cleaning introduced above, DHF cleaning can be performed in the following manner: use a single wafer system to process the cleaning device, spray DHF concentration of 0.5% by mass of hydrofluoric acid at a liquid temperature of 20° C. During the processing time period of the clock, the semiconductor substrate held on the stage is spun (coated).

On the other hand, the ammonia concentration of APM used for APM cleaning is preferably not less than 0.05% by mass, more preferably not less than 0.1% by mass, particularly preferably not less than 0.2% by mass. Also, the ammonia concentration of APM is preferably not more than 1.5% by mass, more preferably not more than 1% by mass, particularly preferably not more than 0.6% by mass.

The concentration ratio of hydrogen peroxide to ammonia in the AMP (hydrogen peroxide/ammonia; reference mass) is preferably not less than 1, more preferably not less than 1.1, particularly preferably not less than 1.2. Also, the concentration ratio of hydrogen peroxide to ammonia in the AMP (hydrogen peroxide/ammonia; reference mass) is preferably not greater than 5, more preferably not greater than 3, particularly preferably not greater than 2.

The etch rate of SiGe tends to decrease as the ammonia concentration of AMP decreases; however, the stripping ability of the particles tends to decrease when the ammonia concentration is too low. On the other hand, the particle exfoliation ability of AMP increases with the concentration ratio of hydrogen peroxide to ammonia in the AMP until a specific ratio is reached. Furthermore, it is not preferable to make the concentrations of hydrogen peroxide and ammonia in the AMP too large in terms of cost.

In this regard, by setting the composition within the AMP within the range introduced above, particles adhering to the semiconductor substrate can be further sufficiently removed while sufficiently suppressing undercutting of SiGe.

In terms of suppressing undercutting or temperature control of SiGe, the working temperature of AMP is preferably not higher than 45°C, preferably not higher than 40°C, particularly preferably not higher than 35°C. Moreover, in terms of temperature control or energy cost, etc., it is preferable that the operating temperature of the AMP is within the range as close as possible to room temperature, and all such as the above temperature ranges are taken as the upper limit, and the allowable tolerance temperature can be set to not less than 5°C, not Less than 10°C, and further not less than 15°C.

When an attempt was made to clean a semiconductor substrate using ammonia water and oxygen-containing water having a high liquid temperature and a high concentration according to a conventional cleaning method, after patterning a gate pattern and a gate oxide film pattern by dry etching, there was no to the extent of the SiGe layer, but the gate oxide film is undercut to some extent. For this reason, in conventional cleaning methods, cleaning conditions are controlled so that the amount of undercut of the gate oxide film is within allowable limits, and degradation of element characteristics does not become a problem, for example, not more than 1 nm. In the present invention, the concentration of the APM composed of the mixture of ammonia water and oxygen-containing water can be lower than that of the conventionally used chemical liquid, so it can effectively suppress or prevent the lateral side of the gate oxide film caused by APM in the APM cleaning process. eclipse. Moreover, in the APM cleaning process, the side erosion of the gate oxide film can be suppressed or prevented, so the allowable upper limit of the amount of side erosion of the gate oxide film can be fully ensured. Hydrofluoric acid, which has oxide properties, can also remove residues while suppressing the amount of undercut of the gate oxide film within allowable limits.

As an example of the APM cleaning described above, the APM cleaning can be carried out in the following manner: a single wafer system is used to process the cleaning device, and the composition of APM is 30% by mass of ammonia water: 30% by mass of oxygenated water: water=1:1 :50 (volume ratio), sprayed from a nozzle at a liquid temperature of 35° C., and spin (coat) the semiconductor substrate held on the stage during a treatment time period of 30 seconds to 2 minutes.

Preferably, the above-described DHF cleaning and its rinsing process, the APM cleaning process and its rinsing process, and the resist stripping process and its rinsing process are continuously carried out in a cleaning device of a single wafer system. Furthermore, it is preferable to continuously perform the fine post-drying process in a single-wafer system cleaning apparatus. Due to this, transfer of the semiconductor substrate between devices becomes unnecessary, and contamination of the substrate at the time of transfer can be prevented. It should be noted that in order to prevent particle generation, it is preferable to perform alkaline APM cleaning in a process chamber different from the process chamber in which acid chemical fluid treatment (SPM or DHF) is performed.

For a preferred single wafer system cleaning apparatus used in the manufacturing method of the present invention, a resist stripping cleaning apparatus having one processing chamber of a single wafer system provided with a holding unit for holding a semiconductor substrate, a rotation holding in a holding A semiconductor substrate on the unit, a cleaning solution supply unit that supplies a resist stripping solution on the semiconductor substrate on the holding unit, and a rinse solution supply unit that supplies a rinse solution on the semiconductor substrate on the holding unit. When performing another cleaning such as DHF cleaning after the resist stripping process, it is preferable to further include a chemical solution supply unit.

For the single wafer system cleaning apparatus described above, for example, a cleaning apparatus having a processing chamber shown in FIG. 1 can be used. The cleaning apparatus is provided with a turntable 2 holding a wafer 3 in a process chamber 1 . Wafers are held in such a manner that a suction mechanism is provided on the stage 2 or a wafer holding tool is provided on the periphery of the stage. On the stage 2, a resist stripping liquid supply nozzle 4, a rinse liquid supply nozzle 5, and a supply nozzle 6 for another chemical liquid such as DHF etc. are provided, whereby the wafer 3 held on the stage 2 can be provided. A variety of chemical solutions or rinses are available on the The inner surfaces of the processing chamber such as nozzles, tables, etc. or contacting parts of chemical liquids are constructed or coated with chemical-resistant (acid-resistant/heat-resistant) materials such as quarts or Teflon (trademark) and the like. On the bottom of the processing chamber 1 is provided a waste liquid discharge port 7 from which chemical liquid or pure water supplied to the upper surface of the wafer is discharged. Also, a supply port for an inert gas such as nitrogen or argon is provided in order to maintain the process atmosphere at a constant condition, and in this case, an exhaust port may also be provided. Various chemical liquids such as resist stripping liquid etc. are kept in the storage tank at a predetermined temperature, and then are discharged from the supply nozzle by pressure feeding of the feed pump. At this point, the supply line can be coated with thermal insulation, or the temperature can be adjusted with a heater.

When using alkaline chemical liquids such as APM for treatment, after treatment with acidic chemical liquids such as SPM, DHF, etc., it is preferable to provide a cleaning device with the same structure as the treatment chamber described above, instead of providing for the provision of alkaline chemical liquids The nozzles are provided instead of the resist stripping liquid provided separately in one device. The transfer of semiconductor substrates between the different process chambers takes place in such a way that known transfer units are provided.

Next, preferred embodiments of the present invention will be described with reference to the drawings.

first embodiment

FIG. 11 shows a schematic structural diagram of a substrate processing apparatus 100 according to an embodiment. The substrate processing apparatus 100 is provided with a processing chamber 102, including a substrate mount table 104, a first container 126 containing a first liquid provided to the surface of a semiconductor substrate 106, a container containing a second liquid provided to the surface of a semiconductor substrate 106, A second container 130 of liquid, a mixing portion 114, communicates with the first container 126 and the second container 130 to produce the mixture while mixing the first and second liquids provided by these containers, and a nozzle 112, in communication with the mixing portion 114, provides the mixture to the surface of the semiconductor substrate 106 , and a conduit 115 connects a mixing section 114 to a nozzle 112 to introduce the mixture from the mixing section 114 into the nozzle 112 . At the periphery of the pipe 115, a pipe heater 160 (FIG. 17) for heating the pipe 115 is provided.

The substrate mount table 104 holds a semiconductor substrate 106 as an object to be processed. The substrate mount stage 104 connected to the electrode 108 is configured in such a manner that it rotates while keeping the semiconductor substrate 106 horizontal. The semiconductor substrate 106 is rotated with an axis passing through the center of the substrate and perpendicular to the surface of the substrate as the axis. A heating portion is preferably provided at the substrate mounting table 104 or its periphery, whereby the semiconductor substrate 106 is thermally insulated to a predetermined temperature by the heater. Fig. 12 shows an example of such a configuration. In the structure of FIG. 12 , an infrared heater 134 is provided on the substrate mount table 104 , and due to this, the surface of the semiconductor substrate 106 is heated.

The rotation controller 110 controls the rotation speed of the electrode 108 . According to the consideration of the present inventors, it is apparent that during the processing process, in some cases, the processing efficiency is improved by appropriately changing the number of revolutions of the substrate. For example, in the resist stripping process performed in the present embodiment, it is apparent that the resist stripping efficiency is significantly improved in the case where the substrate is rotated at a higher speed initially and then the substrate is rotated at a lower speed.

The reason is not obvious, but it is presumed as follows.

When impurity implantation is performed at a high dose rate, a hardened layer is formed on the surface of the resist. This hardened layer is often difficult to remove. Therefore, the chance of the surface of the semiconductor substrate 106 contacting fresh chemical liquid on the surface of the substrate rotating at high speed is increased; thereby the hardened layer can be effectively removed, thus improving the efficiency of the stripping process. In contrast, after peeling off the hardened layer, the substrate does not have to be rotated at such a high speed, but it is preferable to rotate at a low speed to keep the liquid on the substrate surface for a long time, thereby reducing the consumption of chemical liquid. According to the processing contents described above, the rotation controller can realize the rotation speed distribution. Although there is no particular limitation in the control system by the rotation controller 110, for example, a stage-based system for driving the electrode 108 may be used while maintaining a stage in which time corresponds to the number of revolutions.

The first container 126 and thermal insulator 118 contain a first liquid for processing. In this embodiment, sulfuric acid was used as the first liquid. The first liquid contained in the first container 126 is supplied to the thermal insulator 118 by means of a pump not shown in the figure. Its liquid volume can be adjusted by a control valve 124 . The heater 120 is formed on the periphery of the thermal insulator 118, whereby the first liquid sent out from the first container 126 is thermally insulated to a predetermined temperature. In this embodiment, the predetermined temperature is 80 to 100°C. The first liquid contained in the thermal insulator 118 is sent to the mixing section 114 while its feeding amount is regulated by the control valve 124 .

The second container 130 contains a second liquid for treatment. In this embodiment, oxygenated water is used as the second liquid. The second container 130 is kept at room temperature (20 to 30° C.); the second liquid is directly supplied from the second container 130 to the mixing part 114 . The feeding amount of the second liquid is adjusted by the control valve 128 .

The mixing part 114 mixes the first liquid supplied from the thermal insulator 118 with the second liquid supplied from the second container 130 . For hybrid systems, various forms can be used. An example of the structure of the mixing section 114 is shown in FIG. 13 . As shown in the figure, the mixing part 114 is provided with a pipe 156 composed of a hollow-structured spiral pipe, and the first introduction port 152 and the second introduction port 154 respectively introduce the first liquid and the second liquid into the pipe 156 .

By using the mixing portion 114 of this structure, the first and second liquids are efficiently mixed while moving helically along the inner wall of the mixing portion. Another example of the structure of the mixing section 114 is shown in FIG. 22 . In this example, a tubular heater 166 is provided around the same duct 156 as in FIG. 13 . The pipe 156 is disposed inside the tubular heater 166 . The tubular heater 166 has an inlet 170 and an outlet 168 for hot water, and a heat medium circulates inside it. For example, glass is employed as a constituent material of the tubular heater 166 .

In this embodiment, the first and second liquids, that is, mixed sulfuric acid and oxygen-containing water, generate heat of reaction, whereby the temperature of the mixture is not less than 100° C.; supplying this mixture having a high temperature to the semiconductor substrate 106 increases heat treatment efficiency. However, during the period when the supply of the mixture for the semiconductor substrate 106 is stopped, the mixing portion 114 is cooled, whereby it is expected that the temperature of the liquid remaining inside decreases. Therefore, in the apparatus of FIG. 11, a heater 116 around the mixing portion 114 is provided to suppress cooling of the remaining liquid.

The nozzle 112 provides the mixture produced at the mixing portion 114 to the surface of the semiconductor substrate 106 . The mixture sent from the mixing section 114 is introduced into the nozzle 112 via the pipe 115 . The nozzle 112 sprays the mixture toward a predetermined portion of the semiconductor substrate 106 .

FIG. 17 is an enlarged view of a portion including a mixing portion 114, a pipe 115 and a nozzle 112. The nozzle 112 supplies the mixture, which becomes high temperature due to reaction heat, to the semiconductor substrate 106 . At this time, the processing efficiency of the semiconductor substrate 106 is enhanced, however, it is foreseeable that the temperature of the liquid remaining in the nozzle 112 decreases while the supply for the semiconductor substrate 106 is stopped. Therefore, as shown in FIG. 17, in this embodiment, the heater 162 surrounds the nozzle 112 to suppress cooling of the remaining liquid.

Furthermore, a duct heater 160 is provided around the duct 115 . Due to this, the mixture is maintained at a high temperature while the mixture is sent from the mixing portion 114 to the nozzle 112, whereby the temperature or composition of the mixture can be stabilized.

Next, a processing process using the above device substrate will be described.

In this embodiment, the process performed includes the following steps.

(i) A resist is formed on silicon.

(ii) A resist patterning process is performed.

(iii) Ion implantation is performed using the resist as a mask.

In this embodiment, it is assumed that ion type: As, implantation concentration: 5×10 ¹⁴ cm ⁻² .

(iv) The resist is stripped with a mixture of sulfuric acid and oxygenated water (SPM).

In the above step (iv), the apparatus used is shown in FIG. 11 and the like. Before performing the process (iv), the second container 130 should be prepared in a condition that its interior is filled with oxygen-containing water, and the first container 126 should be prepared in a condition that its interior is filled with sulfuric acid. A predetermined amount of sulfuric acid is introduced from the first container 126 to the thermal insulator 118 for thermal insulation at 80 to 110° C. by the heater 120 . The environment is maintained at this condition and prepared before processing begins. First, the flow rate of the first liquid is adjusted by the control valve 122 , and then the flow rate of the second liquid is adjusted by the control valve 128 to introduce these liquids into the mixing part 114 . In the mixing section 114, they are mixed into SPM. The mixture which reaches a liquid temperature of 100 to 120° C. due to exothermic reaction is introduced onto the surface of the semiconductor substrate 106 by mixing.

The rotational speed of the semiconductor substrate 106 in the heat treatment is controlled in the following condition.

(a) 15 seconds from start: 500 revolutions per minute

(b) From 15 seconds to 40 seconds: 15 revolutions per minute

Due to (a) above, the resist hardened layer produced by the high-concentration dose rate is effectively stripped. Next, due to (b) above, the resist remaining on the lower portion other than the hardened layer is removed.

It should be noted that the rotational transformation of the wafer may take many forms other than those described above. For example, Fig. 6 shows an example of it.

Furthermore, the diagrams shown in FIGS. 18 to 21 are preferably taken.

In the diagram shown in Figure 18, the hardened layer on the peripheral portion of the wafer can be peeled off, the number of revolutions returns to high speed rotation again, and new SPM at high temperature is sprayed entirely on the wafer, due to this, a small amount of remaining resist on the surface Agent residues are completely removed.

In the diagram shown in FIG. 19, the resist surface hardened layer by I/I (ion implantation) was formed thickly by repeating high-speed rotation and low-speed rotation, and the hardened layer was not peeled off at the time of high-speed rotation/SPM transfer. The area becomes larger. Therefore, at this time, in one high-speed to low-speed rotation process, it is impossible to completely remove the hardened layer at low-speed rotation. For this reason, the area of the resist hardened layer left at the time of final low-speed rotation becomes small. Repeat high speed rotation/transfer and low speed rotation again. Due to this, the resist can be efficiently removed.

Similar to the diagram of FIG. 19 , the diagram shown in FIG. 20 is an effective processing method in the case where the I/I-dependent resist surface hardening layer is formed thickly. Similar to the diagram of FIG. 18 , by final High-speed rotation and transport during processing completely removes the small amount of remaining resist residue on the surface.

Similar to the diagram of FIG. 19, the diagram shown in FIG. 21 is an effective processing method in the case where the I/I-dependent resist surface hardening layer is formed thickly. Sulfuric acid softens the hardened layer, and in the second stage, resist dissolution and removal is carried out through the SPM. Also, similarly to the diagram of FIG. 20 , SPM transfer of high-speed rotation at the time of final processing is performed. For the stripping of the ion-implanted resist, it is preferable to perform single-wafer SPM processing after photoashing. For example, in 1E15 ion-implanted resists, photoashing is preferably followed by single-wafer SPM processing during a 20 to 60 second time period.

The effects of the device and method are described below according to this embodiment.

The device according to the present embodiment employs a system in which the first and second liquids are mixed in the mixing part 114, the mixture (SPM) becomes high temperature by the heat generated during the above mixing, and the mixture having a high temperature is sprayed on the semiconductor substrate 106.

The temperature of the liquid is raised by the heat of reaction mixed immediately before spraying onto the semiconductor substrate 106, therefore, there is no need to provide an additional heating mechanism, whereby the processing liquid is made high temperature with a simple structure, and processing efficiency can be improved.

Furthermore, in the present embodiment, the downstream side (semiconductor substrate 106 side) from the mixing portion 114 becomes a structure thermally insulated by the heater. For this reason, the mixture whose temperature is increased due to the heat of reaction can be supplied to the semiconductor substrate 106 without substantially lowering the temperature. Thanks to this, an effective optimal treatment can be achieved temperature-wise.

Also, the apparatus according to the present embodiment employs a single-wafer system processing wafer-by-wafer using a processing liquid instead of a soaking system in which many wafers are immersed in the same processing liquid. In a soaking system, the contaminants removed from the surface of the wafer are dissolved or dispersed in the aqueous solution, after which easy re-adhesion of the contaminants to the backside of another adjacent wafer occurs. In this regard, the present embodiment performs single-wafer system processing, so this problem does not occur, whereby a higher degree of cleanliness can be achieved.

Also, in the present embodiment, a constitution in which the first and second liquids are mixed in advance in the mixing portion 114 and then sprayed from the nozzle 112 is employed. Peroxosulfate H ₂ SO ₅ is generated by mixing two liquids inside the mixing portion 114 of the airtight structure, and the mixture including a fixed amount of peroxosulfate is sprayed to the semiconductor substrate 106 from the nozzle 112, and therefore, it is possible to Preferable resist stripping efficiencies are foreseen. Although the conditions under which caro's acid is likely to be generated are not necessarily clear, it is foreseeable that in the case where two liquids are mixed in the mixing portion 114 of an airtight structure as the present embodiment, there is a tendency to stably generate caro's acid. As will be described later in this example, it is difficult to obtain a stable resist stripping efficiency during discharge of the mixed liquid from the nozzle, and thus it is necessary to provide a mixing portion of an airtight structure as this embodiment.

Also, in the present embodiment, sulfuric acid and oxygen-containing water are mixed once in an airtight space, and then further heated by the heater 116 while maintaining caroic acid (oxide species) generated by mixing into the SPM liquid. Due to this, the peeling efficiency can be stably improved.

second embodiment

This embodiment illustrates providing the semiconductor substrate 106 with a mixture sprayed by two nozzles. FIG. 14 shows an example of a substrate processing apparatus 100 according to an embodiment. 15A, 15B are views showing the positional relationship between the nozzles 112a, 112b and the semiconductor substrate 106 shown in FIG. 14 . Except for the nozzle structure, the device structure of this embodiment is the same as the device structure shown in the first embodiment. The point of setting the heater around the pipe 115 and the nozzle 112 is the same as indicated in the first embodiment.

As shown in FIGS. 15A and 15B , the nozzle 112 a sprays the mixture to the end portion of the semiconductor substrate 106 , and the nozzle 112 b sprays the mixture to the center portion of the semiconductor substrate 106 . The nozzle is prepared at an angle "a" to the substrate surface and an angle "b" to the tangential direction of the substrate.

In this embodiment, in addition to the effects described in the first embodiment, the following effects are exhibited.

The device according to the present embodiment is provided with two nozzles of a nozzle 112a and a nozzle 112b. The structures are such that one sprays the processing liquid to the central portion of the semiconductor substrate 106 and the other sprays the processing liquid to the end portions of the semiconductor substrate 106 . Due to this, in the processed surface of the semiconductor substrate 106, the temperature becomes uniform, and thus the resist stripping efficiency becomes uniform. Although the present embodiment utilizes the heat generated by the mixing of two liquids to make the treatment liquid high temperature, at this time, in the surface of the semiconductor device 106, a difference in temperature distribution easily occurs between the position where the liquid directly hits and the position where the liquid does not hit. . Therefore, the stability of the process can be improved in such a manner that a plurality of nozzles are prepared as above, and then a method is formed to cause the liquid to impinge on different positions of the semiconductor substrate 106 .

third embodiment

In this embodiment, an example in which the mixture is sprayed onto the semiconductor substrate 106 is shown. FIG. 16 shows an example of the substrate processing apparatus 100 in the embodiment. Except for the nozzle structure, the device structure of this embodiment is the same as the device structure shown in the first embodiment. Points of the pipe 115 and the heater around the nozzle 112 shown in FIG. 17 are the same as those in the first embodiment. As shown in the figure, in this device, the nozzle 112 can move due to the control of the moving part 140 . The nozzle 112 is constructed to spray the mixture while moving the sprayed portion from the center of the substrate to the peripheral portion. In the above structure, within the processed surface of the semiconductor substrate 106, the temperature becomes uniform, whereby the resist stripping efficiency becomes uniform. Although the present embodiment shows that the processing liquid is made high temperature by heat generated by mixing two liquids, at this time, in the surface of the semiconductor device 106, a difference in temperature distribution easily occurs between a position where the liquid directly hits and a position where the liquid does not hit. Therefore, as described above, the treatment is performed while moving the sprayed portion of the liquid, and due to this, the stability of the treatment can be improved.

Fourth embodiment

Using the apparatus indicated in the above examples, after the resist stripping process by SPM, the rinsing process was performed by the following two systems.

(i) Pure water rinsing treatment

(ii) Rinsing treatment with pure water, with diluted ammonia water after rinsing

The time required for the rinsing process by the system (ii) is shorter than the time required for the system (i) to complete the rinsing process.

It should be noted that the same tendency was obtained for the system (ii) since dilute APM (aqueous ammonia peroxide) or alkali-reduced water was also used instead.

As described above, the preferred embodiment of the present invention has been described by taking the resist stripping process as an example.

The remaining resist here has a tendency to be easily generated at the peripheral end of the wafer. Due to this, the following is presumed.

The first reason is that differences in temperature distribution easily occur within the wafer surface. The peripheral end portion of the wafer tends to become colder than the wafer middle portion, and thus it is expected that the resist stripping efficiency decreases in the peripheral end portion of the wafer.

The second reason is that the resist hardened layer adheres firmly to the peripheral end of the wafer. Generally, the resist is formed so that the film thickness becomes gradually thinner generally from the middle portion of the wafer toward the peripheral end. That is, the film thickness of the resist is formed such that the central portion is thick and the peripheral end portions are thin. In the peripheral end portion of the wafer, the upper portion of the resist becomes a resist hardened layer, and when the resist hardened layer is peeled off, the lower portion of the resist is easily peeled off by a peeling action. On the other hand, in the peripheral end portion of the wafer, the thickness of the resist is thin, so almost the entire resist deteriorates to a hardened layer, so it cannot be expected to peel off the resist by a lift-off action as in the middle portion of the wafer. For this reason, in the peripheral end portion of the wafer, it is difficult to remove the resist hardened layer, compared with the central portion of the wafer.

The third reason is that it is difficult for the treatment liquid to remain on the surface of the peripheral end portion of the wafer. In the peripheral end portion of the wafer, sliding of the processing liquid tends to occur, whereby the processing efficiency deteriorates.

In this regard, in this embodiment, the following measures are taken to effectively deal with the resist remaining at the peripheral end portion of the wafer.

As mentioned in the first reason above, when the mixing portion 114 is provided in an embodiment, the mixture (SPM) is conditioned to control the temperature immediately before being provided to the semiconductor substrate 106 . Due to this, the temperature distribution within the wafer surface can be made uniform. If a constitution in which a plurality of nozzles 112 is provided as in the second embodiment, or a constitution in which movable nozzles are employed as in the third embodiment, the temperature uniformity is further improved.

Also, regarding the contents described in the second and third reasons, in the above embodiments, the rotation controller 110 properly controls the number of revolutions of the substrate, and due to this, the slipping of the processing liquid at the peripheral end of the wafer is suppressed and the Efficiency of the resist hardened layer. For example, after processing at a higher number of rotations, processing is performed at a lower number of rotations, so that slippage of the treatment liquid hardly occurs and the treatment liquid is easily held at the peripheral end of the wafer.

For these reasons, in the embodiment, the remaining resist at the peripheral end of the wafer is effectively dissolved.

As described above, the embodiments of the present invention have been described with reference to the drawings, however, these are descriptions of the present invention, and various configurations other than those described above can be employed.

For example, in the above-described embodiments, SPM is used as the processing liquid, if the resist pattern can be effectively stripped by processing with a single wafer system after dry etching, a substance other than SPM may be used. For the resist stripping solution described above, for example, solvents containing phenol and halogen-based solvents as main components, amine-based solvents, and ketone-based solvents such as cyclopentanone, methyl ethyl ketone, and the like can be used. Resist after dry etching along with its surface denaturation, whereby usually the solubility of the solvent is low compared to the resist before dry etching, so resist residues tend to remain, so it is preferable to perform stripping with high resist Effective SPM cleaning. The composition of SPM can be set as sulfuric acid: 30% by mass oxygenated water = 1:1 to 8:1 (volume ratio); the working temperature is in the range of 100 to 150°C. By this measure, the preferred peeling performance and cleaning efficiency can be stably improved.

Also, in the above embodiments, the processing of a silicon substrate is taken as an example, however, there may be various semiconductor substrates, such as semiconductors including elements such as Si, Ge, etc., depending on the purpose of application. Among them, when a silicon wafer is used as the semiconductor substrate, the effects of the present invention are further significantly exhibited.

In the above embodiments, the stripping treatment of the resist was taken as an example, however, "treatment" in the present invention includes treating the entire substrate surface with a chemical liquid or its vapor. For example, wet etching treatment, stripping treatment stripping residue, and the like are included.

[example]

[example 1]

A SiGe gate pattern as a transistor is formed on the silicon wafer according to the above method by photolithography technology and dry etching technology, and the gate length is less than 100nm. The gate pattern has a portion having a width not greater than 150 nm and a high contrast width not less than 1.

In order to remove the excess resist pattern after dry etching, SPM cleaning was performed using the single wafer system cleaning apparatus shown in FIG. 1 under the following conditions. Next, drying treatment was performed by performing rinsing treatment with pure water using the same single wafer system cleaning apparatus.

SPM composition provided: sulfuric acid/30wt% oxygen-containing water=1/1 (volume ratio), SPM delivery amount to wafer surface: 100 to 200 ml, SPM temperature: 100° C., SPM processing time: two seconds.

[Comparative example 1]

Similar to Example 1, a wafer on which a SiGe gate pattern was formed was prepared. In order to remove excess resist patterns after dry etching, SPM cleaning was performed using a immersion type system using a quartz tank according to the following conditions. Next, drying treatment was performed after rinsing treatment with pure water using a immersion system using a different quartz tank.

SPM composition provided: sulfuric acid/30wt% oxygen-containing water=5/1 (volume ratio), processing tank: quartz tank with a volume of 45L, number of wafers processed in one batch: 50, SPM temperature: 140°C, SPM processing time: ten seconds.

[Assessment of the number of particle deposits]

The measurement of the number of particles adhering to the wafer surface of the wafer in which the processes were performed in Example 1 and Comparative Example 1 while using a wafer defect inspection apparatus (KLA-TencorCompany 2351) was performed. The results are shown in FIG. 2 .

[Evaluation of metal deposits]

The measurement of the amount of Ge attached to the wafer surface of the wafer in which the processing was performed in Example 1 and Comparative Example 1 was performed using a commercially available wafer surface inspection device (total reflection type X-ray fluorescence analyzer). The results are shown in FIG. 3 . It should be noted that, for Comparative Example 1, Ge deposits on the wafer surface after processing 1000 wafers were measured.

[Evaluation of the number of pattern peelings produced]

The measurement of the amount of pattern peeling generation was carried out in which the processing was performed in Example 1 and Comparative Example 1 while using a wafer defect inspection apparatus (KLA-Tencor Company 2351). The results are shown in FIG. 4 . No pattern peeling was observed on the wafer of Example 1. It should be noted that for Comparative Example 1, the results in the case of adding megasonic waves with a frequency of 950 kHz and an output of 120 W for 10 minutes to the rinsing process are shown.

From the above evaluation results, it can be seen that according to the present invention, the attachment of particles or metal impurities on the wafer surface can be effectively suppressed without damaging fine patterns.

[Example 2]

In this embodiment, an example of a manufacturing method of a semiconductor device is shown, including:

(i) a step of forming a resist pattern on the upper portion of the semiconductor substrate,

(ii) a process of processing the exposed portion using the resist pattern as a mask,

(iii) A step of supplying a resist stripping liquid to the resist pattern of the semiconductor substrate while keeping the semiconductor substrate rotated horizontally to form a surface peeling resist pattern.

Specifically, step (iii) is a step of forming a SiGe gate pattern and simultaneously performing dry etching on the polysilicon into which impurities have been introduced.

The operation (iii) of stripping the resist pattern comprises:

a first step of supplying a resist stripping solution to the resist pattern forming surface while rotating the semiconductor substrate at a relatively high speed, and

After the first step, there is a second step of supplying a resist stripping solution to the resist pattern forming surface while rotating the semiconductor substrate at a lower speed.

This will be described in detail below.

First, a SiGe gate pattern with a gate length not greater than 100 nm is formed on a silicon wafer. Afterwards, using the resist pattern as a mask, ion implantation is performed on the N-MOS region and the P-MOS region respectively to generate impurities for the purpose of suppressing the short channel effect. In each ion implantation process, the dose is not less than 10 ¹⁴ cm ^-2 .

The process flow is shown in Figure 5. Here, in a process in which the resist pattern does not need to be stripped after ion implantation, SPM cleaning is performed in the order shown in FIG. 6 using the single-wafer system cleaning apparatus shown in FIG. 1 . That is, cleaning is performed by the first step of applying the resist solution under the high-speed rotation condition and the second step of applying the resist solution under the low-speed rotation condition. When impurity introduction at a high dose rate was performed as an example, a resist hardened layer was generated within the resist pattern. The resist hardened layer can be effectively stripped by the second step described above.

It should be noted that although not shown in the figure, the SPM temperature, composition, pure water rinsing and drying process were the same as in Example 1. Further, after this flow, sidewall oxide film formation and source-drain implantation are performed, whereby a transistor is formed.

[Comparative example 2]

After the ion implantation of Example 2, the process of stripping the resist pattern was performed using the soaking system shown in Comparative Example 1.

[Evaluation of number of defects after resist pattern stripping]

Similar to Example 1, the number of defects was evaluated after stripping using the KLA resist pattern. The results are shown in Figure 7.

Resist residue did not occur in both Example 2 and Comparative Example 2, however, in Comparative Example 2, pattern peeling or graining occurred. Pattern peeling due to megasonics.

In Example 2 and Comparative Example 2 using single-wafer cleaning, there was no damage because no megasonic was used, no complete pattern peeling occurred, and the number of generated particles was suppressed to a small number because there was no backside transfer.

Also, with a larger ion implantation amount not less than 1E ¹⁴ /cm ² , the resist could be effectively stripped only by the single wafer cleaning of Example 2, although a hardened layer was formed on the resist surface. This is caused by the order of the arrangement shown in FIG. 6 . That is, first, in order to peel off the hardened layer, the SPM liquid is continuously conveyed for a time period of 9 seconds while the wafer is rotated at a high speed. During this high-speed spinning step, the number of contacts between the wafer and the SPM fluid increases, due to which the hardened layer is significantly removed. Afterwards, the number of rotations is reduced to a low speed, and after the SPM liquid is transmitted for a time period of 10 seconds, the transmission is stopped in order to save the chemical liquid, and the raised liquid of the SPM liquid in the central part of the wafer is diffused to the outer peripheral part of the wafer by centrifugal force, under the hardened layer The softer resist layer is stripped (paddling). A small amount of remaining hardened layer in the periphery is peeled off at this time by peeling. It should be noted that when the high-speed rotation is continued and there is no agitation, the temperature of the liquid decreases in the outer peripheral portion of the wafer, resulting in residue separation. Therefore, this procedure is effective in the resist stripping of this embodiment as a hardened layer remaining on the surface caused by ion implantation. It is to be noted that the resist stripping process in Fig. 8 (1 to 5) is a schematic diagram.

[Example 3]

In Example 2, instead of H ₂ SO ₄ +H ₂ O ₂ , the liquid provided was H ₂ SO ₄ +Caro's acid (H ₂ SO ₅ ). The resist stripping of SPM has been obtained by the principle that Caroic acid (H ₂ SO ₅ ) produced by mixing H ₂ SO ₄ and H ₂ O ₂ has a strong oxidation effect, and the resist is oxidatively decomposed by Caroic acid. Therefore, even if H ₂ SO ₄ complexed with caroic acid is used, the same effect as the SPM of H ₂ SO ₄ +H ₂ O ₂ can be obtained. In this regard, the liquid supply mechanism can be simplified due to the single supply structure. The same evaluation as in Example 2 can be obtained with the H ₂ SO ₄ complexed with the caroic acid, and it can be confirmed that the same results can be obtained (Fig. 9, Fig. 10).

It is obvious that the present invention is not limited to the above description, and modifications and changes may be made without departing from the scope and spirit of the present invention.

Claims (25)

1. A method of manufacturing a semiconductor device, comprising: forming a resist pattern on the upper portion of the semiconductor substrate; processing using the resist pattern as a mask; and peeling off the resist pattern while supplying a resist stripping liquid to a resist pattern forming surface of the semiconductor substrate while rotating the semiconductor substrate while keeping the semiconductor substrate horizontal, Wherein the step of stripping the resist pattern comprises: supplying the resist stripping liquid to the resist pattern forming surface while rotating the semiconductor substrate at a relatively high speed; and The resist stripping solution is supplied to the resist pattern forming surface while rotating the semiconductor substrate at a lower speed as a second step after the first step. 2. The method of manufacturing a semiconductor device according to claim 1, wherein in the step of performing the processing, ion implantation is performed on the entire surface of the substrate using the resist pattern as a mask. 3. The manufacturing method of a semiconductor device according to claim 2, wherein the dose in said ion implantation is not less than 10 ¹⁴ cm ^-2 , and the resist produced in the resist pattern caused by ion implantation is stripped by said second step. etchant hardened layer. 4. The manufacturing method of the semiconductor device according to claim 1, further comprising: the resist pattern is formed on a film provided on the semiconductor substrate; and In the step of performing the processing, dry etching of the conductive film is selectively performed using the resist pattern as a mask to form a fine pattern of the film. 5. The manufacturing method of a semiconductor device according to claim 4, wherein said fine pattern has a portion having a width of not more than 150 nm. 6. The manufacturing method of a semiconductor device according to claim 4, wherein said fine pattern has a portion having a width of not more than 150 nm and a height-to-width ratio of not less than 1. 7. The manufacturing method of a semiconductor device according to claim 4, wherein said fine pattern is a gate pattern. 8. The method of manufacturing a semiconductor device according to claim 7, wherein said gate pattern is a SiGe gate pattern having a SiGe layer containing Si and Ge. 9. The method of manufacturing a semiconductor device according to claim 7, wherein said gate pattern is a polysilicon or amorphous silicon gate pattern. 10. The method of manufacturing a semiconductor device according to claim 7, wherein said gate pattern is a metal gate pattern. 11. The method of manufacturing a semiconductor device according to claim 1, wherein a liquid containing caroic acid is used as said resist stripping liquid. 12. The method of manufacturing a semiconductor device according to claim 1, wherein said resist stripping liquid is an organic solvent. 13. The manufacturing method of a semiconductor device according to claim 1, wherein the first liquid containing acid and the second liquid containing hydrogen peroxide are mixed in an airtight space, and the obtained mixture is used as said resist stripping liquid, said A resist stripping liquid is supplied to the resist pattern forming surface through a nozzle. 14. The manufacturing method of a semiconductor device according to claim 13, wherein said first liquid or said second liquid is preheated to a predetermined temperature. 15. The method of manufacturing a semiconductor device according to claim 13, wherein said first liquid is sulfuric acid, and said second liquid is oxygen-containing water. 16. The manufacturing method of a semiconductor device according to claim 1, comprising supplying sulfuric acid to a resist pattern forming surface of said semiconductor substrate before said first step. 17. The manufacturing method of a semiconductor device according to claim 1, wherein said resist stripping liquid is supplied to said resist pattern forming surface through a plurality of nozzles. 18. The manufacturing method of a semiconductor device according to claim 1, wherein said resist stripping liquid is heated to a predetermined temperature in advance, and thereafter, said resist stripping liquid is supplied to said resist pattern forming surface. 19. The manufacturing method of a semiconductor device according to claim 1, further comprising: performing a rinsing treatment of the semiconductor substrate after the step of stripping the resist pattern; In the step of performing the rinsing treatment, performing the rinsing treatment while supplying the rinsing liquid onto the semiconductor substrate; and The semiconductor substrate held by the holding unit is dried by rotating the semiconductor substrate with the rotating unit. 20. The method of manufacturing a semiconductor device according to claim 19, wherein said rinsing liquid is alkaline liquid, electrolytic cathode water, or water in which hydrogen gas is dissolved. 21. The manufacturing method of a semiconductor device according to claim 19, further comprising: cleaning the semiconductor substrate with the resist pattern peeled off with hydrofluoric acid; and The semiconductor substrate that has been cleaned with hydrofluoric acid is cleaned with a mixture of ammonia water and oxygen-containing water. 22. A resist stripping cleaning apparatus having a processing chamber for a single wafer system, comprising: a holding unit for holding a semiconductor substrate; a rotation unit that rotates the semiconductor substrate held by the holding unit; a cleaning solution supply unit that supplies a resist stripping solution onto the semiconductor substrate held by the holding unit; and A rinse liquid is supplied to a rinse liquid supply unit on the semiconductor substrate held by the holding unit. 23. A resist stripping cleaning apparatus having a first process chamber for a single wafer system and a second process chamber for a single wafer system, wherein The first process chamber for a single wafer system includes: a holding unit for holding a semiconductor substrate; a rotation unit that rotates the semiconductor substrate held by the holding unit; a cleaning solution supply unit that supplies an acid resist stripping solution onto the semiconductor substrate held by the holding unit; and a rinse liquid supply unit that supplies a rinse liquid onto the semiconductor substrate held by the holding unit, and The second process chamber for a single wafer system includes: a holding unit for holding a semiconductor substrate; a rotation unit that rotates the semiconductor substrate held by the holding unit; a cleaning solution supply unit that supplies an alkali resist stripping solution onto the semiconductor substrate held by the holding unit; and A rinse liquid is supplied to a rinse liquid supply unit on the semiconductor substrate held by the holding unit. 24. The resist stripping cleaning apparatus according to claim 22, further comprising: a heating unit that heats the resist stripping unit; and A thermal insulation unit that thermally insulates the heated resist stripper. 25. The resist stripping cleaning apparatus according to claim 23, further comprising: a heating unit that heats the resist stripping unit; and A thermal insulation unit that thermally insulates the heated resist stripper.

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